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    <title>Document</title>
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    <script>
        // 1、打印100以内的所偶数 的 和
        var sum = 0;
        for (var i = 1; i < 100; i++) {
            if (i % 2 === 0) {
                sum += i;
            }
        }
        console.log('100以内的所有偶数之和：' + sum)
    </script>
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